The invention deals with a device for sectioning a metal wire. In particular, it is for cutting or chopping into sections or small pieces the electrode wire evacuated by a machine which cuts by electroerosion. The mechanical and electrostatic properties of the used wire electrode which is generally made of copper or by laying copper and/or copper brass on a core of steel, conduct to a wire which will possess a strong tendency for expansion in the receptacle or container in which it is stockpiled, which necessitates frequent intervention by the operator to compress the wire, because it forms not very dense entanglements which occupy rapidly the entire available space in the receptacle.
In effect, the wire is evacuated at a certain speed, between 7 and 14 m/min., and it conducts, if one wants to achieve automatic functioning the duration of an entire weekend, as an example, from an average stockpile of 37 km. of wire without human intervention. It is therefore necessary to compact it. But to this day, no satisfactory alternative to compacting without human intervention is known, and this prevents an autonomous functioning of EDM machines that cut with wire.
It is known to curl the electrode wire by making it pass between two toothed wheels, or also to cut it into small pieces which posses the capability of accumulating in a relatively dense pile. Devices of this type are described by patents U.S. Pat. No. 4,016,395, G.B. 2.010.160, DE b 35 11 930, JP 56-89441(A), JP 57-61422, JP 57-61423 which all relate to the field of electroerosion. In the two initial patents, the cutting tools are mounted on a rotating member which sections against anvil, which anvil does not rotate with a surface plane, concave and immobile with regard to the wire. Said anvil conducts therefore to a rapid wear of the cutting tools, in particular when the shopped electrode wire is difficult to section. An example would be a wire composed of copper and zinc. The worn cutting tools becoming inoperable and in the absence of an operator, the wires accumulate. By accumulating, wires hinder normal movement and provoke short circuits and general deterioration of the machining.
The further cited patents utilize rotating anvils, which are more advantageous. But the device described in patent DE 35 11 930 requires a floating bearing mounted in a very complicated structure with a spring and an oscillating arm for obtaining elasticity between tool and anvil. In the device described by patents, JP 56-89441, JP 57-61422 and JP 57-61423 said elasticity is obtained by a particular configuration of the cutting tools. But this complicates the forming of the tools and requires care in their alignment, with very strict tolerances, because the wire to be cut in small pieces has a diameter of only one-tenth of a millimeter. So then if one tool slightly shrinks with regard, to the other, it does not section the wire but to the contrary by projecting beyond its alignment the anvil or hammers the wire pieces into the anvil, if said anvil is not made of an extremely hard material. Elsewhere this is why a rotating brush is provided to clean the anvil which is encrusted with cut pieces of wire. Other devices, although they are not conceived for cutting small pieces of metal wire, which consist of a rotating blade and anvil are described in the following patents: U.S. Pat. No. 3,677,122 which concerns a process for continuously cutting (and not for discontinuously cutting as in the present invention), with ring-shaped blades, the cutting edges of which are parallel to the movement of a band in order to cut said band longitudinally with an anvil presenting radial elasticity. U.S. Pat. No. 3,828,637 and GB 1 000 696 relate to devices in which the rotating anvils do not present radial elasticity, but which describe rotating tools which could eventually be utilized in the present invention.
The object of the present invention is a device for sectioning a wire in a great number of pieces, which comprises two rotating members on parallel axes. These members rotate in opposite directions, the wire translating between them. The flange of one member acts as an anvil while the flange of the other member acts as a tool in which at least one cutting blade is mounted, such as to have its cutting edge positioned parallel to the axis of rotation of the members. In it's construction it is simple, yet sturdy and economical in its functioning. The design does not promote rapid wear and tear of the blades and permits elasticity in the pressure exerted by the anvil on the blades. The latter present a very simple configuration and setting up on the tool. This permits easy replacement of dulled blades, at any time, and facilitates rapid changes, without the need of a complicated adjustment. Said device is characterized by an anvil which is mounted around a radially elastic and rotating support surrounding the axis of rotation. In particular, this anvil can be constituted of a cylindrical sleeve which clasps at least one elastic ring surrounding a central core cylinder which is solidly attached to the rotating shaft. One thus obtains an elasticity in the pressure of the tool on the anvil even when the levels of the two rotating members remain motionless during the functioning of the chopping tool. Manifestly, this notably simplifies the construction when compared to available solutions. Moreover, since either the tool, or the anvil, or both,undergo brusque acceleration at the moment the two strike each other, it is advantageous for the question of longevity, that the elastically suspended part has a small inertia, which the invention favors since only the anvil is elastically suspended and not a whole rotating member as is the case with the known devices presenting an elastic suspension.
The above-mentioned application, in which the anvil is a sleeve resting on two elastic rings maintained in grooves, permits further the easy and unexpensive replacement of the anvil when it is used.
The invention is now illustrated by the description of one mode of execution and with the aid of the annexed drawings in which :